Undercover Gardening -- When The Weather Outside Is Frightful, Your Greenhouse Can Be Delightful

HOWEVER WE CARE to explain it, our species seems to have a manifest desire to hold dominion over the fowl of the air and the beast of the field, and at some long-forgotten crossroad we came to include the carrot and the orchid. It was at that moment that the concept of the greenhouse was born.

For when speaking of greenhouses, at root we are talking about control: control of sunlight, temperature, water, soil and nutrients - plants' basic needs. Elsewhere in the garden we can only pretend we're gods and goddesses, but in the greenhouse, what we say goes.

This wasn't always the case. In the 17th century, greenhouses were simple brick or timber shelters with a few windows and basic heat. They served only to keep frost off tender evergreens. As glass became cheaper, heating more sophisticated and exotic plants more available, freestanding greenhouses evolved into today's familiar roofed and walled glass (or polycarbonate or plastic-film) structures. By many accounts, the form reached an aesthetic zenith in the enormous Crystal Palace, built of glass, iron and laminated wood in Hyde Park in 1851 to house London's Great Exhibition.

Today we use the prosaic vernacular of a weatherman to name greenhouses by type.

A "warm" greenhouse, heated to a minimum temperature of 55 degrees, allows the cultivation of tropical and subtropical plants and ensures year-round flowers (though often at the expense of a large heating bill).

A "cool" greenhouse can drop to 45 degrees and that's fine for a great number of tender plants. Keeping one just above freezing preserves fuchsia baskets, potted geraniums and chrysanthemums without problem, so long as plants are kept dry enough to stay dormant.

An unheated greenhouse can be useful even in subfreezing temperatures, provided it is kept well-ventilated. Control wind, water and insects and the reward is unblemished early flowers from bulbs, plus hardy cuttings or grown plants in the spring.

Keeping this in mind, take a look at the ways these gardeners have learned to get the most out of growing under cover in the Northwest.

Living the dream

TO JIM WIGGINS and Elizabeth Binney, "greenhouse effect" is a beautiful phrase. The Sedro-Woolley couple built their house around a hybrid solarium-greenhouse that holds about 200 orchids.

Being inside the solarium is like standing inside a pair of lungs because it functions as a giant heat pump. The concrete floor holds heat, small fans move warm air through the 22-foot-high solarium, and strategically placed inner windows at the top of the "air shaft" route warm updrafts to the adjoining living space. There, intake ducts, more windows and an even taller ceiling channel heat to the rest of the house.

On a dreary winter day it is 71 degrees inside, after just two hours of sunlight. Orchids and bromeliads bloom and free-range anoles skitter behind potted banana plants.

A small propane heater stands by in winter to make sure temperatures don't dip below 55 degrees. An overhanging eve keeps sun from scorching plants in summer.

Wiggins and Binney, who are biological consultants, spent a year hashing out details with their architect, Clive Pohl, of Pohl + Pohl in Seattle.

They hired Janigo Construction in Bellingham for most of the work. Lindal Sunrooms engineered and executed the curved cedar framing of the solarium according to Pohl's specifications.

"You have to keep on top of the closed environment - the humidity and the rest," Wiggins says. "It's fun if it's a part of your lifestyle. We have a good time with it."

A top-of-the-line greenhouse

A FREESTANDING greenhouse can be a handsome architectural element in the landscape. Cynthia Wheeler's 11-by-15-foot Renaissance greenhouse, designed and sold by Architectural Glass Inc. of Seattle, is that and more. Here is a hefty aluminum framework coated with baked-on color. It has clear insulated glass and top-of-the-line materials throughout. There are modern venting systems combined with old-fashioned details. Metal work and finishing details are impressive.

For Wheeler, a physician, the greenhouse is a soothing place to sit quietly and welcome the day, surrounded by flowers on the potting bench. In spring, she looks up through pink clouds of magnolia blossoms.

On the practical side, Wheeler grows many annuals from seed and overwinters tender plants in containers. She also roots cuttings of friends' favorite shrubs and returns them as new plants.

The greenhouse is heated to 50 degrees in winter. It has electricity, a phone line, running water, sophisticated lighting system and a stone floor. It rests on a stuccoed knee wall. Site preparation and assembly were by professional builders. All in all, the structure looks to be built for the ages. Wheeler describes it in one word: beautiful. The total cost - roughly $150 a square foot - makes the Renaissance comparable in price to a solarium.

Simple, but nice

RON rICHTER IS a serious plantsman. The dentist, who lives on Mercer Island, calls his Hall's greenhouse essential for overwintering borderline-tender plants. The English-style structure, purchased through Cottage Creek Nursery in Woodinville, is a kit-type greenhouse, the kind two people can assemble over a weekend.

It's attractive in a functional sort of way, with double-strength glass, a rain gutter, a vent and a handsome crown - all desirable features. Richter finds it efficient, carefully made and, well, cute. He chose this style and size because he wanted to keep things simple.

Still, it caused something of a row with a landscape-standards committee at his development, called the Lakes. "But neighbors wrote a letter of support. They considered my efforts to be an improvement."

He paid about $1,000 for the 6-by-8-foot, glass-and-aluminum-frame structure, about $200 to have it painted dark green at an industrial-painting place, and another $200 to have it assembled.

He prepared the site himself by leveling it, setting concrete block at the corners, then placing four 4-by-6-inch treated timbers as a foundation. He secured the timbers to the ground with rebar and the greenhouse rests atop the timbers. A wood-chip floor can be moistened to boost humidity. A small electrical heater holds the temperature just above freezing. He overwinters about 30 plants in containers and clears it out in the summer.

Richter pats his Hall's gently. He says he wouldn't be without it.

Dean Stahl is a Seattle writer and editor. Gary Settle is Pacific Northwest magazine's picture editor. ------------------------------- RESOURCES

Check the Yellow Pages and "The Northwest Gardeners' Resource Directory" by Stephanie Feeney. On the Web:

www.gardenweb.com

www.orbitworld.net/hga Both will point you to information and sales sources.

Many mail-order companies offer kit greenhouses, including Gardener's Supply Co. (800-863-1700).

Charley's Greenhouse Supply in Mount Vernon is one of the largest sellers of kit-style greenhouses and supplies in the country. Web: www.charleysgreenhouse.com

(For a free catalog: 800-322-4707.)

The Yard Works in Lynnwood is a source for greenhouses in many styles (425-787-6603).

Cottage Creek Nursery, Woodinville. Sells kit-style greenhouses and some supplies (425-883-8252).

Architectural Glass Inc., Seattle, offers high-quality custom greenhouses and conservatories (206-284-6947).

Steuber Distributing Co. in Snohomish sells wholesale and retail greenhouse supplies. Call for free catalog (800-426-8815).

Sunglo Greenhouses, Auburn, sells kit-style "Acrylic Plexiglass" greenhouses (253-833-4529).